Pulse-count coder



PULSE-COUNT CODER Filed May 17, 1956 2 sheets-sheet 1 Q www Y m. Musa.

(NGT

INVENTOR United States Patent C) PULSE-COUNT CODER t Application May 17,1956, serialNo. 585,494

9 claims. (ci. 340-341) The invention relates to a pulse-count coderwhich in response to incoming pulses produces a coded output signalrepresenting the number of input pulses.

Many uses exist in electronic systems, such as computers and `controldevices, for devices producing a coded output signal corresponding tothe number of input signals or pulses. The coded output signal or pulsesmay be used for Various indicating and control functions, in lthe latteroften serving as gating pulses `to control the energization ortransmission of electrical energy to various utilization devices.

In many instances, the nature of the code is deter mined by theapparatus to which the output of the counting device is to be applied.It therefore becomes desirable to have a counting device which iscapable of producing an output in accordance with :an arbitrarilyselected code. Moreover, to accommodate any required change in thecontrol function of the output signals from the counting device, it isdesirable to be able to change the code in which the count is expressed.

These requirements for arbitrary coding and for ilexibility in changingthe code are not easily met; and conventional devices have, in general,not proven satisfactory or have been of relatively limited application.

An object of the present invention is the provision of an improveddevice for producing a coded output signal expressing according to anarbitrary code the number of input pulses.

Another object of the present invention is the provision of a device ofthe type hereinbefore described in which the particular code in whichthe count is expressed may readily be changed into another arbitrarycode.

Other and further objects of the present invention will become `apparentand the foregoing will be better understood with reference to thefollowing description of embodiments thereof, reference being had to thedrawings, in which:

Fig. l is a block diagram of a device for producing an arbitrarily codedoutput signal corresponding to the number of sequential input pulses; j

lFig. 2 is a schematic diagram of the embodiment represented n blockform of Fig. l arranged to produce an Excess-3 Gray coded signal output;and

Fig. 3 is a chart of the Excess-3 Gray Code.

Referring more specifically to Fig. l, there is shown in block form fourtrigger-responsive bistable stages A, B, C and D which may be, forexample, in the form of multivibrators. Each `stage controls `a diodematrix conguration and is connected thereto through appropriateconnecting leads. The trigger input pulses 11 are applied to triggergate 13, which pulses, depending upon the unique conditions of the gate,are transmitted to the Various ones of the counter stages A, '13, C andD. The unique conditions of the trigger gate are controllable directlyby the matrix 10 which is, in turn, controlled by the trigger-responsivestages A, B, `C `and D.

Turning now to Fig. 2 wherein a detailed schematic 2,845,617 PatentedJuly 29, 1958 drawing of the invention is illustrated, the operation ofa speciiic embodiment of the invention will be described in conjunctionwith a particu-lar chosen code, namely, the Excess-3 Gray Code of whicha chart is shown in Fig. 3. Four bistable trigger circuits of themultivibrator type are illustrated, namely, stages A, B, C and D; andthe output signal from each of the trigger circuit outputs represents adiierent digital position in the output pulse code selected. Forexample, if only stage C produces an output signal, then the count ornumber of input pulses would be 4, as noted from the Excess-3 Gray CodeChart in Fig. 3. On the other hand, if only stages B and D were toproduce an output signal, then yagain with reference to Fig. 3, thenumber of pulses that would be counted would be 9.

As will be shown, the code chosen is determined by the ldiodearrangement in the diode matrix 10. Fig. 2 shows the matrix diodearrangement necessary to produce Ithe Excess-3 Gray Code illustrated inchart form in Fig. 3. There are ten diode matrix lines numbered from 0to 9 in consecutive order. Each line is connected to a positive sourceof potential B+ through a coupling resistor 22. The trigger gatingcircuit 13 is -comprised of Ia group of diodes, the anode of each diodebeing connected to a separate one of the matrix lines and the cathodesof the diodes being tied together to form a common connection 63 to line64 to which the input pulses 11 are applied..

v'With reference to Fig. 3, the chart shows that for a count of 0 thebistable stages A, C and D produce no output signals whereas bistableIstage lB does develop an output signal. Under these conditions, theright triodes 30, 32 and 34 of stages A, C and D, respectively, areconductive whereas the left triode 36 of stage B is conductive. Theoperation of bistable multivibrators is such that normally one of a pairof cross-connected electron tubes is conducting, the othernonconducting. To reverse this condition, a triggering pulse is appliedto the stage so that one of the tubes, theconducting one, is biased tocutofr. The conduction of triodes 30, 32 `and 34 of stages A, C and D,respectively, biases the matrix diodes on matrix lines l through 9,inclusive, but not the zero v(0) matrix line. The conducting triode 30of stage A has associated therewith a series of matrix diodes 40, 41, 42and 43, each diode being associated with matrix lines 2, 3, 6 and 7,respectively. The cathodes of the diodes 40, 41, 42 and 43 are connectedtogether and tied to thte anode 45 of triode 30 whereas their respectiveanodes are separately tied to the associated matrix line. Whenever amatrix `diode is conducting, the matrix line normally associated withsuch diode has a potential whose value is less than that of the B+supply voltage by an amount equal to the voltage drop `across thedropping resistor 22. Consequently, the matrix lines 2, 3, 6 and 7 areat a reduced potential when triode 30 of stage A is to stage B, triode31 is conducting when the -count is O placing diodes 51, 52, 53 and 54in a conductive state which, in turn, causes a reduction in voltage ofthe matrix lines 3, 4, 5 and 6 associated with each of the said diodes.Likewise with respect to stage C, triode 32 is also conducting at the 0count placing diodes 56 and 57 in ya conductive or unblocked conditionwhich puts matrix lines l and 8 at reduced voltages with respect tothesupply voltage. Finally, triode 34 of stage D, being also conductiveat the O count, renders matrix diodes 58, 59, 60, 6l and 62 :conductivethereby effectively placing matrix lines 5, 6, 7, 8 and 9 at reducedpotentials. It may be noted that in certain instances there areoverlapping matrix diodes, e. g., more than one matrix diode associatedwith a matrix line; but this does not atect the count operation. Oneillustration of this conducting. With respectl is that matrix line 5 has`diodes 53 and 58 both coni yductively associated therewith. IFrom theforegoing, it is seen that for a count of 0 the matrix lines from l to 9have reduced potentials whereas matrix line zero (0) retains itsoriginal potential 'equal to that vof the "B+ supply voltage.

A trigger-gate arrangement 13 is 'associated with the matrix-linearrangement in such a manner that the matrix controls the transmissionlof triggering pulses 1'1 through the trigger gate 13 to the bistablemultivibrator stages. The trigger gate 13 comprises va series of diodeseach having its anode 60 connected separately to a single matrix line.The cathodes 62 `of these diodes are connected to a common point 63which, in'turn, is connected to the input line 64 to kwhich the'triggering impulses 11 are applied via a coupling capacitor 66. Line 64is also connected to the potential 'supply source 20 'to couplingresistor 22. When the count is 0, as heretofore explained, matrix linesl through 9, inclusive, are at 'areduced potential; and the diodes ofthe trigger gate 13 connected to lines l through 9 are thereby 'blockedbecause their anodes are at a 'reduced potentialwith respect to theircathodes. Thus, a 'negative input trigger pulse along line 64 cannotpass through any of the diodes associated with matrix lines l through 9.However, the diode in trigger gate 13 which is connected to the zero (0)matrix line is not blocked, and the incoming negative pulse passes thisdiode and thence lthrough decoupling diode 66 via conductive lead 68 tobistable stage C. The negative trigger pulse by means of thecrosscoupling arrangement in stage C is coupled to the 'grid electrode70 of triode 32 and causes the said triode 32 to become nonconductivewhile the triode 36 of stage C starts to conduct. Now two stages,namely, stages B and C, have their left triodes 31 and 36 conducting'thereby producing signals at their outputs 76 and 78, respectively. Thechart of Fig. 3 shows that for output signals from stages B and C thecode represents a count of 1" input pulse.

When the left triode 36 of stage C conducts, the right triode 32 becomesnonconducting. Therefore, no 'current can flow through diodes y56 and 57of the matrix. Consequently, the potential of matrix vline l will riseto that of the B+ source. The potentialof matrix line 8 will not rise,however, since matrix diode 61 connected to line 8 is still conductingthrough conducting triode 34.

With matrix line 1 at its higher potential, the next negative inputtrigger pulse on linev 64 will pass through that diode of trigger gate13 which is connected to matrix line l since that diode is unblocked.This negative input trigger pulse reaching matrix line l passes viaconnection 83 and decoupling diode S6 to stage A and through thecross-connection to the grid to triode 30 blocking said triode 30 andcausing triode 80 to conduct. An output signal is thereby produced atoutput terminal 82. Under these conditions, triodes 80, 31 and 36 areconducting providing outputs at 76, 78 and 82 `which in the Excess-3Gray Code Chart represent the count of "2.

The counting continues in this manner with each input pulse being fedthrough the open trigger gate and decoupling diode to trigger theappropriate multivibrator stage, the proper trigger-gate diode beingopen for conduction by the potentials of the matrix lines as determinedby the conduction of the matrix diodes, the conduction of the matrixdiodes, in turn, being controlled by condition of the multivibratorstages.

It will be apparent that the matrix diodes may be rearranged to providedifferent codes for expressing the input-pulse count. Greaterflexibility in changing the code is lprovided by the fact that theconnections from the trigger-gate diodes to the different triodes of themultivibrator stagesmay also be changed.

It will be obvious that many changes may be made in the arrangementdisclosed without departing from the teachings of the present invention..Amongst these obvious changes is the replacement of the electrondischarge diodes and triodes by the equivalent solid-state rectiers andtransistors. In place of the classical multivibrator stages, otherstages having a plurality of stable operational levels may also beemployed. Changes in the arrangement of the matrix and the use of otherforms of similar organizations are -also envisaged by the presentinvention. y

Accordingly, while I have ldescribe above the principles of my inventionin connection with specific apparatus, 'it is vto be clearly understoodthat this description is made only by way of example and not as alimitation to the scope of my invention as set forth in the objectsthereof and in the accompanying claims.

I claim:

l. A pulse-count coder for producing a code output representative of thenumber of input pulses from a pulse source comprising a plurality ofcode-producing stages each having a plurality of stable operationallevels, a diode matrix consisting of a plurality of matrix vconductorsand groups of matrix diodes coupled to said conductors, means 'couplingsaid matrix diodes to said stages to produce potentials on saidconductors determined by the particular operational level at which theassociated stage is operating, and means including a plurality of gatecircuits coupled to and controlled by the potentials of said matrixconductors for kapplying said input pulses to different points of saidstages in accordance with a predetermined code.

2. pulse-count coder for producing a code output representative of thenumber of input pulses from a pulse source comprising a plurality yoftrigger circuits each having a plurality of stable operational levels,means including a plurality of gate circuits for applying input pulsesfrom said source to different Ypoints of said plurality of triggercircuits to trip said trigger circuits from one to the other of saidoperational levels, a diode matrix coupled to said gate circuits tocontrol the conductivity of each of said gate circuits, and means forcoupling the diodes of said matrix to different points of said triggercircuits to change the conductivity of said matrix diodes in accordancewith changes in the operational levels of said trigger circuits.

3. A pulse-count coder for producing a code output representative of thenumber of input pulses from a pulse source comprising a plurality oftrigger circuits each having a plurality of stable operational levels,means including a plurality of gate circuits for applying input pulsesfrom said source to dierent points of said plurality of trigger circuitsto trip said trigger circuits from one to the other of said operationallevels, a diode matrix including matrix lines and groups of matrixdiodes coupled to said lines, means for coupling the diodes of saidmatrix to different points in said trigger circuits to change thepotential of vsaid matrix lines in accordance with changes in theoperational levels of said trigger circuits, and means coupling saidmatrix lines to said gate circuits to control the conductivity Vof saidgate circuits in accordance with the potential of said matrix lineswhereby the input pulses are applied to trip 'the trigger circuits inaccordance with a predetermined code.

4. A pulse-count coder for producing a code output representative of thenumber of input pulses from a pulse source comprising a plurality ofcode-producing stages each having a plurality yof stable yoperationallevels, a diode matrix coupled to said stages and producing voltagesdetermined by the particular operational level 'at which the associatedstage is operating, and means including a plurality of gate circuitscontrolled by the voltages from said matrix for applying said inputpulses 'to different points of said stages in accordance with apredetermined code.

l'5. A Coded counter 4system substantially as described comprising aplurality of bistable multivibrator stages 'each having a pair ofselectively conducting triodes responsive to input triggering pulses andan output, a diode matrix array comprising a plurality of code-selectivegroups of non-conductive matrix diodes, said groups being selectivelycoupled to one of said trigger-responsive triodes and adapted to becomeconductive in response to said conducting triode, `a gating circuitadapted to receive pulses from a pulse source and having a plurality ofdiodes disposed to have a common cathode input and individual anodeoutputs, a plurality of matrix lines disposed in said matrix array toselectively engage the said matrix diodes and the output anodes of saidgating circuit, the said matrix lines beingadapted to receive pulsesfrom said gate in response to the said selective conductive changes inthe said matrix diodes, and means for coupling the said matrix-linepulses to the said bistable multivibrator stages in accordance with thesaid preselective code,

6. A coded counter system substantially as described comprising aplurality of bistable multivibrator stages each having a pair ofselectively conducting electron discharge devices responsive to inputsignals and an output, a diode matrix array comprising a plurality ofcodeselective groups of blocked matrix diodes, said groups beingselectively coupled to one of said responsive electron discharge devicesand adapted to become unblocked in response to the said conductingelectron discharge device, a gating circuit adapted to receive pulsesfrom a pulse source comprising a plurality of diodes disposed to have acommon cathode input and individual anode outputs, a plurality of signallines disposed in said matrix array to selectively engage the saidmatrix diodes and the output anodes of said gating circuit, the saidsignal lines being adapted to receive pulses from said gate in responseto the said unblocking of said code selective groups of matrix diodes,and means for coupling said signalline pulses to the said bistablemultivibrator stages in accordance with the said preselected code.

7. A signal translation system for producing a pre determined codedoutput signal responsive to sequential input signals comprising aplurality of bistable multivibrator stages each having a pair of onofftriodes responsive to input triggering signals and an output, a diodematrix array comprising a plurality of groups of matrix diodes, each ofsaid groups being selectively coupled to one of said on-oi triodes andadapted to become blocked when said triode is on and unblocked when saidtriode is oit', a gating circuit adapted to receive pulses from al pulsesource comprising a plurality of diodes disposed to have a commoncathode input and individual anode outputs, a plurality of signal linesdisposed in said matrix array to selectively engage the said matrixdiodes in accordance with said selected code and the output anodes ofsaid gating circuit, the said signal lines being adapted to receivepulses from the said gate when the engaged matrix diode is blocked andno pulse when thesaid matrix diode is unblocked, and means for couplingthe said signal-line pulses to the said bistable multivibrator stages toproduce a signal from them in accordance with the said selective code.

8. A signal translation system for producing a predetermined codedoutput signal responsive to input signals comprising a plurality ofbistable multivibrator stages each having a pair of selectivelyconductingvelectron discharge tubes responsive to input triggeringpulses and an output, a control matrix array comprising a plurality ofcode-selective groups of nonoperative electron discharge devices, saidgroups being selectively coupled to one of said trigger-responsiveelectron discharge tubes and adapted to become operative in response tosaid conducting discharge tubes, a gating circuit adapted to receivepulses from a pulse source comprising a plurality of electron dischargedevices having an anode and a cathode disposed to have a common cathodeinput and individual anode outputs, a plurality of signal lines disposedin said control matrix array to selectively engage the said matrixelectron discharge devices and the output anodes of said gating circuit,the said signal lines being adapted to receive pulses from said gate inresponse to the operative changes in the said matrix electron dischargedevices, and means for coupling said signal-line pulses to the saidbistable multivibrator stages to produce a signal from the said outputthereof in accordance with the said preselective code.

9. A coded counter system comprising a group of bistable lcontrollableflip-Hop circuits, each circuit having a pair of triodes with on-offcharacteristics, a plurality of bias-controlled bus lines, a series ofcontrol diodes interposed between said triodes and bus lines andresponsive to the on-oi characteristics of said triodes, the

` said responsive control diode controlling the bias of said bus lines,a gate circuit including a plurality of diodes each having its anodeseparately connected to said bus lines and its cathode commonlyconnected, the said gate circuit being adapted to receive electricalsignals from a signal source at its cathode and transmit said signals toa controlled bus line, and means for coupling said busline signal to acontrollable ip-op circuit.

References Cited in the le of this patent UNITED STATES PATENTS2,686,299 Eckert Q. Aug. l0, 1954

